He said the story was untrue and he had not been able to think "for the life of me" what the source of the story could be.

The only explanation he could think of was that messages had been left on his phone by an executive's assistant, who had a voice which could be described as "plummy".

"I was preparing these statements, going through these trials and tribulations," he said. "Then the penny dropped."

He added: "I would love to hear what the (Mail on Sunday's) explanation of that is, if it wasn't phone hacking."

Mr Grant gave details of the story after being asked how many times he had brought libel actions.

He said in the past 17 years he had brought libel actions on between six and 10 occasions.

Grant referred to an article published earlier this year about him attending the Accident and Emergency department at Chelsea and Westminster hospital in London.

The article, which appeared in the Sun and the Daily Express, showed him as a celebrity who waited patiently with everyone else in the A and E ward. However, Grant said that by publishing him in a good light the tabloid was trying to "cover a breach of privacy".

He said: "This is an article that says that I went to hospital – it is my medical record saying I was dizzy with shortness of breath – which was a gross intrusion of my privacy.

"I think no one would expect their medical records to be made public or to be appropriated by newspapers for commercial profit.

"That is fundamental to our British sense of decency."

Grant told the newspapers that he would not file a lawsuit if each of the papers would donate £5,000 to Healthtalkonline.

"The Express flatly refused to pay a penny ... the Sun gave £1,500," he said.

He said he believed that someone at the hospital may be "on retainer" for a newspaper or an agency – when the worker would tip off the press if someone famous was to attend.

In April 2007, Mr Grant accepted undisclosed libel damages over claims that his relationship with Ms Khan was destroyed by a flirtation with a film executive – and his conduct over Liz Hurley's wedding.

The settlement of Mr Grant's legal actions over articles in the Mail on Sunday and the Daily Mail in February 2007 was announced at the High Court in London.

He said the first article – Hugh, Drew and the Jealousy of Jemima – alleged that Grant, while in a relationship with Ms Khan, was conducting a flirtation with a female senior Warner Bros executive.

It also claimed that he pretended to Ms Khan that his regular late-night calls with this woman were simply to discuss a movie, that Ms Khan's suspicion was the cause of such acute distress on her part that she barely ate for weeks, and that it was this that had finally destroyed their relationship.

A second article – Guess Hugh's free to join Liz at her wedding after all – asserted that he would be attending Ms Hurley's wedding, would be making a speech and acting as an usher.

It added that as a wedding gift, he had sponsored a chimpanzee at a British zoo and had separately bought an extraordinarily expensive necklace and arranged for it to be inscribed with a personal message from him for Ms Hurley.

The article then alleged that Grant's actions amounted, as far as Ms Khan was concerned, to "a nail in the coffin" and "the last straw", thus causing the end of their relationship.

In addition, it alleged that Grant's gift came despite Ms Hurley's wish to wedding guests that instead of gifts, donations be made to Sir Elton John's Aids Foundation.

A third article – Hugh aren't good enough – alleged that Grant resented having to promote his films.

Mr Smith said that at no stage was any of this put to Grant prior to publication.

He said Mr Grant did not know of a woman from Warner Bros matching this description, let alone that he was conducting a flirtation with her. As far as he was aware, she simply did not exist.

Mr Smith said that the publication of these numerous false allegations in quick succession caused hurt, embarrassment and distress to Grant and damage to both his personal and professional reputations.

Associated Newspapers, publishers of the Daily Mail and Mail on Sunday, offered its apologies and agreed not to repeat the false allegations.

As well as the damages, which Grant made clear from the outset would be donated to charity, it also agreed to reimburse his legal costs in full.

Afterwards, Grant said in a statement: "I took this action because I was tired of the Daily Mail and Mail on Sunday papers publishing almost entirely fictional articles about my private life for their own financial gain.

"I'm also hoping that this statement in court might remind people that the so-called 'close friends' or 'close sources' on which these stories claim to be based almost never exist."